I don't know what its for other than to help align the pinch bolts mulger bill. Personally I'd put it back even if it's damaged as the other function I guessed at when I saw mine was that it acts like a washer and stops the bolts from loosening over time. The stupid things seem over complicated but some shimano engineer somewhere thinks they are important.

So we get the leaders we deserve and we elect, we get the companies and the products that we ask for, right? And we have to ask for different things. – Paul Gildingbut really, that's rubbish. We get none of it because the choices are illusory.

It's a little safety device I think, Personally I find it annoying and chuck it away... Running 4 different cranksets with out an issue. Most important thing is that you put ZERO pressure on the star nut on the end of the crank when doing it up before locking the two Allen bolts up.

My assumption is that the "Stopper Plate" has no function other than to indicate that the left crank is in the correct position on the axle - well that and prevent law suits when incorrectly installed cranks fall off. That plastic and pin is not going to hold ANYTHING.

TLL when you say zero pressure on the star nut, Ive always done it up with the the tool with my fingers until I feel some resistance. I would have thought the plastic would strip before you cold put too much side load on the bearings?

Thanks lads Looks like the allegedly important bit is there so I'll just keep an eye on it.

Toolong, it's very good to know that YOU can live without them, if your left cranks don't fall off because of the lack of them then this 60watt bulb faces zero risk

As to the star nut thingy, I thought its purpose was the same as the top cap in a threadless headset, there to preload the bearings before locking the system together with the pinch bolts? I've always done it up enough to remove any play in the crank then loosened it a micron once I've torqued the bolts. Wouldn't be surprised if I've got this wrong

Thanks again.

Shaun

...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.London Boy 29/12/2011

According to a Hope mechanic, it is tighten the star thingy, then loosen it until it is just not rattling. Anything more will load the bearings and make more wear.

There was a video somewhere on replacing BB...

As for the tab thingy, I've broken some of mine. As long as you keep the bolts tight and the plastic cap thingy in the end, it shouldn't be a problem. Also you should be able to tell when the cranks are becoming loose, before they fly off.

Mulger bill wrote:As to the star nut thingy, I thought its purpose was the same as the top cap in a threadless headset, there to preload the bearings before locking the system together with the pinch bolts? I've always done it up enough to remove any play in the crank then loosened it a micron once I've torqued the bolts. Wouldn't be surprised if I've got this wrong

Thanks again.

Shaun

Yep, it's a pre-load widget. Do it up finger tight with the proper tool and then do up the pinch screws.

the BB bearings are cartridge bearings - i wouldn't have thought you could cause them to bind by overtightening the star nut. it's primary purpose is to ensure there is no lateral slack in crank axle. if you do it up finger tight, you can't go wrong. i always give the drive side cranks a gentle tap with hammer handle to ensure it butts up against the drive side bearings - it can easily bind and let you tighten the LH crank bolts with slack still there (i.e. tightening the star bolt won't always overcome the binding force).

may be a bit late on this..... but the "thingo with the pin' I am pretty sure is to keep the crank in place (stop it coming off) if the bolts get lose and there's no star nut - you have to flip it up and out of the groove so the crank can come off.